Means for pulling thread in a shoe stitching machine



y 30, 1961 c. N. LESTAKIS 2,986,104

MEANS FOR PU LLING THREAD IN A SHOE STITCHING MACHINE Filed Sept. 5, 1958 3 Sheets-Sheet l I 75 I 9 K /7// 1/ y ML li/ivi/J 40 f T I rzfi/ar fig, 0 A /7 G39 m.

MEANS FOR PULLING THREAD IN A SHOE STITCI-IING MACHINE Filed Sept. 3, 1958 C. N. LESTAKIS May 30, 1961 5 Sheets-Sheet 3 United States Patent '6 2,986,104 MEANS FOR PULLING THREAD IN A SHOE STITCHING MACHINE Christy N. Lestakis, 3004 27th Ave., S., Minneapolis, Minn. Filed Sept. 3, 1958, Ser. No. 758,832 3 Claims. (Cl. 112-57) My invention relates to the thread-pulling means on lock stitch sewing machines employed in sewing soles on shoes.

The principal objective of my invention is to pull the necessary thread when the enlarged bobbin mechanism set forth in my Patent 2,686,483 is used.

A further objective is to be able to use my enlarged bobbin mechanism on the Landis stitcher and maintain its present work clearance of without re-designing much of said machine.

In the above mentioned patent I pointed out the desirability of increasing the thread capacity of the present Landis stitcher but have been unable to get this done because the Landis people say that it is an impossibility without re-designing the entire machine and that would run into hundreds of thousands of dollars because of the many forgings required.

I have discovered a way to use my bobbin arrangement which has three times the thread capacity of the present Landis bobbin.

I have incorporated my enlarged bobbin arrangement in a Landis stitcher without encroaching on its work clearance.

I have devised a mechanism which can pull the extra thread required with the enlarged bobbin without changing other than the present thread-pulling mechanism.

How I have accomplished the above is illustrated in the accompanying drawings in which Fig. 1 is an end elevation showing the relative position of the cam and cam lever, the thread tensioning device, the auxiliary take-up mechanism, the thread lock lever, the take-up lever, and the auxiliary take-up lever; Fig. 2 is a front elevation of the above elements; Fig. 3 is a top and end view of the take-up lever; Fig. 4 is a top and end view of the cam lever; Fig. 4A is a vertical section on the line 4A4A of Fig. 4; Fig. 5 is a top and end view of the thread lock lever; Fig. 5A is a section on the line 5A-5A of Fig. 5 showing how the thread is clamped between the thread lock lever and the lock sheave; Fig. 6 is a diagram of the path the thread takes from the supply spool to the looper in my improved machine; Fig. 7 is a diagram of the path the thread takes in the present Landis machine.

Throughout the drawings and the specification similar numerals refer to similar parts.

Since one of my objectives is the application of my enlarged bobbin arrangement to a particular stitcher, namely, the Landis I will tie in my thread-pulling arrangement as it applies to that particular machine.

Since I am re-building the thread-pulling mechanism of the present Landis stitcher using many elements as they are at present and others modified it is believed that it is not necessary to go into the detailed construction of the old elements and their operation beyond what is necessary for one skilled in the art to carry on.

This machine includes a column 1 on the top of which are positioned two spaced apart bearings only the one adjacent the cam which operates the thread-pulling mechanism being shown.

In this bearing 2 and its mate is journalled the cam shaft 33 on which are mounted the four cams which impart movement to the several stitcher mechanisms. The cam 3 serves to operate the thread-pulling mechanism in both the present stitcher and my improved stitcher.

2,986,104- Patented May 30, 1961 ice An arm 4 is cantilevered out from the cam shaft bear reception of a fixed pin 6 about which the bifurcated hub 7 of the cam lever 8 may turn. In the upper end of this cam lever 8 is the fixed collared pin 9 upon which is con fined and rotatable the cam roller 10 which cooperates with the groove 3A in the cam 3 formed to give the desired movement to this cam lever 8. p

The opposite or lower end of the cam lever 8 is tapped for the reception of the threaded shouldered hinge pin 11 upon which one end of the connecting link 12 is mounted.

The other end of the connecting link 12 is mounted on a similar pin 13 threaded into the end 14 of the rocker arm 15 shown integral with the shaft 16 which also has integral therewith a second arm 17, commonly known to the trade as the take-up lever, spaced from and at a right: angle to the arm 15.

This L-shaped arm or take-up lever 17 has an end portion 17A whose included angle to the main portion" 17B of said arm approximates degrees. At the inter section of the median lines of these arm portions is positioned a sheave 18 journalled on the collared pin 19 threaded into the arm 17. At the end of the arm portion 17A is positioned a second sheave 20 journalled on a similar pin 21 whose end is threaded into the arm portion 17A and further secured by the nut 21A.

The ends 16A and 16B of the shaft portion 16 are turned down, the end 16A being journalled in the bearing 22 formed on the end of the arm 23 cantilevered outfrom the column 1. The opposite end 16B is journalled in a bearing 24 formed in what is known as the auxiliary take-up bracket 25 which is secured to the column 1.

A flat spring 26 has one end 26A secured by the screw 26C to the arm 23 and the other end 26B formed to bear against the end of the shaft end 16A, the object being to create a constant end pressure on the rocker shaft 16 to lock lever 28. This quadrant gear 29 is mounted on the shaft 31 and is operable by a rocker arm 32 on said shaft which is connected by a system of elements to one of the operating cams. The system or cam has not beeru shown since they are used as at present and thus well known to those familiar with the Landis stitcher.

The end opposite the tooth 30 on the thread lock lever 28 is formed with an arcuate surface 33 approximating that of the lock sheave 34 mounted on the pin 35 supported by the column 1 and a width approximating the distance between the lock sheave flanges 34A. During each operating cycle the arcuate surface 33 of the thread lock lever 28 is lifted into contact with the lock sheave 34 to clamp therebetween the thread T being pulled for a predetermined period of the operating cycle.

This thread lock lever 28 like the cam lever 8, the connecting link 12, and the take-up lever 17, are modified in my new construction and said modification will be taken up in detail later in the discussion.

There are three old mechanisms in the present Landis thread-pulling means that I incorporate in my new threadpulling means which remain unchanged in form, function, and relative position with one exception. These are known as the auxiliary thread take-up mechanism 36, the

spasms In my improved thread pulling means a slightly greater up and down movement of the sheave 36A is required. The method of providing for the additional movement will be discussed later on. One end of the auxiliary thread take-up mechanism 36 is hingedly connected to the pin 36C supported by the take-up bracket 25. On the free end of said mechanism 36 is mounted the sheave 36A whose upward movement is limited by the adjustable stop screw 25A mounted on the auxiliary take-up bracket 25 and whose downward movement is limited by the stop 25B on the same bracket 25. The spring 36D is formed to lift the free end of the auxiliary thread take-up mechanism 36 into contact with the adjustable stop screw 25A. The form, function, and adjustment of this spring 36D remains the same as in the present Landis" shoe stitcher.

In my improved thread pulling means I use the thread tensioning mechanism 37 of the present Landis shoe stitcher without change in form, function, adjustment, or position, hence further discussion appears to be unnecessary.

In my improved thread pulling means I also use the auxiliary thread tensioning mechanism 38 of the present Landis shoe stitcher without change in form, function, adjustment, position, or the means to cause its operation. It is believed that this mechanism 38 and its operating means is so well known to all skilled in the art that further description is unnecessary.

Fig. 6 of the drawings shows the path of the thread T from the thread supply spool 39 to the looper (not shown) in my improved thread-pulling means for the Landis stitcher. In order to make it easy for one skilled in the art to differentiate between the above mentioned improved thread-pulling means and the thread-pulling means used on the present Landis stitcher it is believed necessary and desirable to show the path taken by the thread T in the present Landis" stitcher. Fig. 7 shows said path.

The path of the thread T in the present Landis stitcher (as shown in Fig. 7) is from the thread supply spool 39 up through the wax heater 40 and over and around the thread tensioning mechanism 37 and then up and over the sheave 38A on the auxiliary thread tensioning mechanism 38 then down and around the lock sheave 34 and between the arcuate portion 33 on the thread lock lever 28. From there the thread T passes up and over the sheave 36A on the auxiliary thread take-up mechanism 36 and then down and around a single sheave 41 carried on the end of the present take-up lever and up to the looper (not shown).

The path of the thread T in my improved thread-pulling means (as shown in Fig. 6) will be described shortly.

Because of the path the thread T takes, as last described, I am able to pull aproximately 2 /2" more thread than can be pulled in the present Landis stitcher. This extra 2 /2 of thread permits the use of a bobbin which has three times the capacity of the bobbin now in use on the present Landis stitcher.

The modifications made in the present Landis threadpulling means include:

(1) Decreasing the distance between the centers of the pin 6 and the pin 11 of the cam lever 8 approximately (2) Increasing the hole centers of the connecting link 12 approximately (3) Adding an angular extension to the take-up lever 17 and positioning the extra sheave 20 thereon.

(4) Providing an opening or hole 33A in the arcuate portion 33 of the thread lock lever 28 for the passage of the thread T downwardly therethrough in the new method of engaging the elements of the thread-pulling means.

(5) Providing additional movement of the auxiliary thread take-up mechanism 36 by re-leaving the stop dog 36B thereon, or, as an alternate, re-leaving the stop 25B on the auxiliary bracket 25.

(6) A new path of travel for the thread T between the '4 elements which make up the thread-pulling means of the improved Landis stitcher.

By making the several changes which I have described I have obtained the added thread necessary to the use of my larger bobbin without having to change the cams and other parts of the Landis" machine.

Although my disclosures apply in particular to the machine of one company I do not limit the use of my invention to that machine but extend it to all that comes fairly within the scope of the appended claims.

What is claimed as new over the art follows:

1. In a shoe stitching machine having thereon a looper; a thread supply spool; a thread tensioning mechanism positioned above the thread supply spool and having a sheave as a part thereof; an auxiliary thread tensioning mechanism positioned above the thread tensioning mechanism, and having a sheave as a part thereof; and an auxiliary thread take-up mechanism having a sheave as a part thereof; in combination with; a thread lock sheave mounted below the auxiliary thread tensioning mechanism; a pivotally mounted thread lock lever having an arcuate end portion formed to engage a portion of the perimeter of the lock sheave and having an aperture therein to permit the downward passage therethrough of thread being pulled from the spool; means to periodically effect contact between the arcuate portion of the thread lock lever and the thread lock sheave to clamp thread being.

pulled therebetween; a pivotally mounted substantially L-shape thread take-up lever having a main portion and a shorter end portion angularly disposed to the main por-' tion said take-up lever having a sheave mounted adjacent the intersection of the median lines of said portions and a second sheave mounted adjacent the outer end of the shorter portion of the take-up lever the position of both sheaves being below the thread lock sheave and the auxiliary thread take-up sheave when thread is being clamped between the thread lock sheave and the thread lock lever;

and means operable when thread is not being clamped between the thread lock sheave and the thread lock lever to cause the take-up lever and the sheaves mounted thereon to be moved outwardly and upwardly from the former position to pull thread downwardly through the aperture in the thread lock lever for delivery to the looper, the

path of the thread from the thread supply spool to the looper being from said spool up to the sheave on the thread tensioning mechanism, up to the sheave on the auxiliary thread tensioning mechanism, down to the thread lock sheave, down through the aperture in the thread lock lever to the inner sheave on the thread take-up lever, up to the sheave on the auxiliary thread take-up mechanism, down to the outer sheave on the take-up lever and 'up to the looper.

2. The structure of claim 1 in which the included angle between the main portion of the L-shape thread take-up lever and the shorter end portion thereof approximates degrees.

3. The structure of claim 1 in which the thread lock lever has portions over which the thread being pulled may be pulled downwardly thereover by the thread take-up lever.

References Cited in the file of this patent UNITED STATES PATENTS 

